Can clonal plants live forever?

August 17, 2010

Despite the many cosmetic products, surgical treatments, food supplements, and drugs designed specifically to reverse the biological effects of aging in humans, long-lived aspen clones aren't so lucky. Researchers at the University of British Columbia have shown that as long-lived male aspen clones age, their sexual performance declines.

Dilara Ally, who conducted this research for her Ph.D., also showed that with that loss of sex and sexual fitness, ultimately the lineage could go extinct. The findings will be published next week in the online, open access journal .

A clone is a group of genetically identical individuals that originate from a single ancestor without the need of sex (for instance cuttings from a plant). Although many organisms can propagate clonally, this feature is most common in plants. In aspen, or clonality is achieved via underground lateral roots that eventually produce new clone members/ramets.

Although a clone can produce new members asexually and avoid meiosis (the stage where parental genomes recombine), it still continues to undergo cell division over the years. As the clone spreads and new trees replace old trees, the number of mitotic cell divisions increases, resulting in an accumulation of along the way. Ally and colleagues used a to estimate the age of individual clones. To do this they measured the number of accumulated mutations at microsatellite markers and calibrated the clock using an independent, geological estimate of time. By coupling estimates of clone age with a measure of male fertility, they found that long-lived aspen clones do indeed suffer reduced sexual fitness with age.

"One reason the evidence for aging in trees is scarce is because it is very difficult to obtain long-term demographic data. Imagine trying to follow cohorts of plants that live on average 100 years of age and don't start reproducing until they are 25 yrs; its impossible within the timeframe of a Ph.D. or even over an entire career," says lead author Ally, who will be taking a postdoctoral position at San Diego State University in the Fall.

The study is a major step toward answering some fundamental questions about aging in plants because it may offer an alternative way to collect data on long-lived clones, using molecular-based estimates of clone age. Ally and colleagues hope that given the advances in sequencing technologies, future research will apply the method to learn whether other plant species show similar sexual fitness declines with clone age.

Explore further: Alternative to cloning technique does not yield pure clones, scientists report

More information: Ally D, Ritland K, Otto SP (2010) Aging in a Long-Lived Clonal Tree. PLoS Biol 8(8): e1000454. doi:10.1371/journal.pbio.1000454

Related Stories

Genetic differences influence aging rates in the wild

December 12, 2007

Long-lived, wild animals harbor genetic differences that influence how quickly they begin to show their age, according to the results of a long-term study reported online on December 13th in Current Biology, a Cell Press ...

Texas-sized tract of single-celled clones

March 11, 2009

A Rice University study of microbes from a Houston-area cow pasture has confirmed once again that everything is bigger in Texas, even the single-celled stuff. The tests revealed the first-ever report of a large, natural colony ...

Study finds role for parasites in evolution of sex

July 6, 2009

What's so great about sex? From an evolutionary perspective, the answer is not as obvious as one might think. An article published in the July issue of the American Naturalist suggests that sex may have evolved in part as ...

Recommended for you

Some vaccines support evolution of more-virulent viruses

July 27, 2015

Scientific experiments with the herpesvirus such as the one that causes Marek's disease in poultry have confirmed, for the first time, the highly controversial theory that some vaccines could allow more-virulent versions ...

Mammoths killed by abrupt climate change

July 23, 2015

New research has revealed abrupt warming, that closely resembles the rapid man-made warming occurring today, has repeatedly played a key role in mass extinction events of large animals, the megafauna, in Earth's past.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.